如何在 EJB 3 实体中使用 Java Reflection API？

发布于 2024-08-19 23:37:54 字数 1404 浏览 5 评论 0原文

我使用 eclipse 3.5、JBoss 4.2、EJB3 执行以下步骤，但遇到类未找到异常

1.将此代码编译到 foo.jar 文件

package mypackage.foo;
import myejbpackage.ejb.fooInterface; 
class foo implements fooInterface{
 @override
 void helloWorld(){System.out.print("HelloWorld");}
     }

请注意，fooInterface 接口是在使用的 EJB 内部编写的

2.使用反射，我举一个实例从此类，也具有相同的 ejb

package myejbpackage.ejb;
class fooCaller{
    void call(){
     Class foo=  Class.forName("mypackage.foo.foo");

fooInterface iDataBackupWriter =(fooInterface) foo.newInstance(); fooInterface.helloWorld(); } 3.

然后在无状态 ejb3 中调用它

package myejbpackage.ejb;
test(){        
  System.Out.Write("before calling");
   new fooCaller().call();
    }

4.然后部署到 Jboss 4.2 并将 foo.jar 放入 default/lib

5.然后调用 ejb 3 方法。使用简单客户端

打印：

 "before calling"

中出现以下异常

  javax.ejb.EJBException: java.lang.RuntimeException: java.lang.NoClassDefFoundError:                       myejbpackage/ejb/fooInterface; nested exception is: java.lang.RuntimeException: java.lang.NoClassDefFoundError: myejbpackage/ejb/fooInterface
 java.lang.RuntimeException: java.lang.NoClassDefFoundError:myejbpackage/ejb/fooInterface

并且在 eclipse控制台建议？ 1.这是JBOOS的异常吗？为什么？ 1.我应该把 foo.jar 放在哪里才能与 ejb3 jar 一起看到？

提前致谢

原文

I do the following steps with eclipse 3.5 ,JBoss 4.2 ,EJB3 but I face class not found exception

1.compiling this code to foo.jar file

package mypackage.foo;
import myejbpackage.ejb.fooInterface; 
class foo implements fooInterface{
 @override
 void helloWorld(){System.out.print("HelloWorld");}
     }

Note that fooInterface interface in is written inside the used EJB

2.using reflection , I take an instance from this class, also with the same ejb

package myejbpackage.ejb;
class fooCaller{
    void call(){
     Class foo=  Class.forName("mypackage.foo.foo");

fooInterface iDataBackupWriter =(fooInterface) foo.newInstance();
fooInterface.helloWorld();
}
}

3.then calling it within stateless ejb3

package myejbpackage.ejb;
test(){        
  System.Out.Write("before calling");
   new fooCaller().call();
    }

4.then deploying to Jboss 4.2 and and puting foo.jar in default/lib

5.then calling the ejb 3 method.using simple client

it print :

 "before calling"

and the following exception occurs in eclipse console

  javax.ejb.EJBException: java.lang.RuntimeException: java.lang.NoClassDefFoundError:                       myejbpackage/ejb/fooInterface; nested exception is: java.lang.RuntimeException: java.lang.NoClassDefFoundError: myejbpackage/ejb/fooInterface
 java.lang.RuntimeException: java.lang.NoClassDefFoundError:myejbpackage/ejb/fooInterface

Any suggestion ?
1.Is this exception from JBOOS, why ?
1.Where I should put the foo.jar to bee seen with the ejb3 jar ?

thanks in advance

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